1. Field of the Invention
The present invention relates to an apparatus for severing a movable web which passes adjacent thereto. More particularly, the present invention relates to a guillotine for making transverse cuts through a printed paper web. In greatest particularity, the present invention relates to a guillotine where a cutting blade is uniformly advanced towards and retracted from the web it is to cut and where the blade is substantially self-aligning with its associated anvil.
The invention is hereinafter described with reference to its use in the cutting of a moving paper web after that web has been printed on an electrically operated printer in an autoteller for providing a bank customer with a written record of a transaction. This application is given only by way of example and the present invention is applicable in any circumstance wherein a web of any severable material passes adjacent to a guillotine.
2. The Prior Art
It is known to provide a guillotine for cutting a movable paper web wherein a cutting blade is advanced towards the paper web to urge the paper web against a supporting anvil for the blade to pass through the paper web into a slot in the anvil and thereby sever the web. It is further known to provide that the leading edge of the blade is provided with a plurality of pointed teeth placed adjacent to one another in linear array. The points of the teeth first penetrate the paper web, the midsections of the teeth then enlarge the penetration holes into slits parallel to the blade, and thereafter the final through passage of the blade causes the slits to join and become a single complete scission of the web. It is further known to grind a chisel edge onto the teeth on the leading edge of the blade to facilitate the ease of penetration of the teeth into the web.
The blade, in passing into the slot in the anvil, must be in close alignment therewith. It is necessary to ensure that the paper web is well supported and that the slot in the anvil is narrow or else the paper will merely be pushed into the slot by the blade rather than being cut. The blade is made of very thin material and any misalignment between the narrow slot in the anvil and the blade causes the blade to collide with the anvil. Such collisions cause mechanical damage necessitating the complete replacement of the guillotine or, at very least, of the blade. It is known to provide the blade and/or the anvil with thin shims along the length of the blade or the anvil to position the blade within a few thousandths of an inch in parallel opposition to the slot. This precision manufacture is costly and slow. The risk of damaging the blade if it is advanced while not in alignment with the slot makes assembly and servicing very difficult. The necessity for grinding many faces on the teeth of the leading edge of a blade makes the cost of the blade and its replacement very high indeed. The necessity for close alignment between the blade and the slot in the anvil limits the amount of bowing permissible in the blade which in turn limits the possible length of the blade so that only relatively narrow paper webs can be so cut.
It is, therefore, desirable to provide a guillotine for cutting a web wherein the requirement for precision in alignment between the blade and the slot in the anvil is relaxed. It is further desirable to provide such a guillotine where the blade is not damaged if advanced when out of alignment with the slot. Yet further, it is desirable to provide such a guillotine wherein the blade is formed without the necessity for grinding chisel edges in the leading edge thereof.